[ pid=19441 thr=2888301424 file=ext/apache2/Hooks.cpp:822
time=2011-09-15 15:45:07.311 ]: The backend application (process
19550) did not send a valid HTTP response; instead, it sent nothing at
all. It is possible that it has crashed; please check whether there
are crashing bugs in this application.

Sometimes I'm also seeing the following error:

[ pid=5805 thr=75783560 file=utils.rb:176 time=2011-09-15 16:02:19.471
]: * Exception PGError in application (SSL SYSCALL error: EOF
detected ) (process 5805, thread #):
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:276:in
exec'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:276:in
block in clear_cache!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:275:in
each_value'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:275:in
clear_cache!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:303:in
disconnect!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:202:in
block in disconnect!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:201:in
each'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:201:in
disconnect!'
from
/app/oath/vendor/ruby/1.9.1/gems/activesupport-3.1.0/lib/active_support/core_ext/module/synchronization.rb:35:in
block in disconnect_with_synchronization!'
from
/usr/local/rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/monitor.rb:201:in
mon_synchronize'
from
/app/oath/vendor/ruby/1.9.1/gems/activesupport-3.1.0/lib/active_support/core_ext/module/synchronization.rb:34:in
disconnect_with_synchronization!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in
block in clear_all_connections!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in
each_value'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in
clear_all_connections!'
from
/app/oath/vendor/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in
clear_all_connections!'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/utils.rb:398:in
before_handling_requests'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:204:in
start_request_handler'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:170:in
block in handle_spawn_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/utils.rb:479:in
safe_fork'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:165:in
handle_spawn_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:357:in
server_main_loop'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:206:in
start_synchronously'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:180:in
start'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:128:in
start'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:253:in
block (2 levels) in spawn_rack_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server_collection.rb:132:in
lookup_or_add'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:246:in
block in spawn_rack_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server_collection.rb:82:in
block in synchronize'
from :10:in synchronize'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server_collection.rb:79:in
synchronize'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:244:in
spawn_rack_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:137:in
spawn_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:275:in
handle_spawn_application'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:357:in
server_main_loop'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:206:in
start_synchronously'
from
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/helper-scripts/passenger-spawn-server:99:in
'